The present invention relates to a loose-boss top roller having a simple construction in which a loose-boss is taken out of an arbor which is attached to a cotton spinning frame.
As a top roller of this kind, end bushes are fixed to both ends of an arbor, needle bearings are attached near both ends of the arbor and ball bearings are inserted into ball-grooves of the arbor near the needle bearings. Also, a hard rubber material is fixed to the outside of the loose-boss which is positioned to the outside of the ball bearings and the needle and the ball bearings are respectively inserted into the ball-grooves of the loose-boss. Furthermore, oiling holes are respectively formed from the ends of the arbor to the needle bearings along the center axis of the arbor and caps cover the ends of the arbor to prevent leakage of lubricant.
When the top rollers constituted as shown in FIG. 1 are mounted on a cotton drawing machine, cotton yarns are passed and drawn between the top rollers and under rollers.
However, in such top rollers, the surface of the hard rubber material is worn by the passed cotton yarns and grooves are so formed on the hard rubber material while the cotton yarns are drawn that the required pressure is not added on the cotton yarn. In such case, the loose boss is taken out of the arbor and is attached to a grinding machine, the loose-boss is rotated and the hard rubber material is ground by the grinding machine.
In this top roller, however, for inserting the ball bearing into the inside of the loose-boss, the arbor, without fixing the end bushes in both ends thereof, is inserted into the inside of the loose boss, the ball-groove of the arbor is united with the ball-groove of the loose-boss and a predetermined number of balls are inserted between the ball-grooves of the arbor and the loose-boss by shifting the arbor to one side of the loose-boss. Then, the balls are uniformly positioned in the grooves of the arbor and the loose-boss by shifting the arbor to the center of the loose-boss and the balls are set by a retainer. After the ball bearings are inserted into the loose-boss, needle bearings are inserted and fixed between the arbor and the loose-boss and the end bushes are fixed on both ends of the arbor by screws.
Accordingly, in the top roller, because the ball bearings are inserted between the ball-grooves of the arbor and the loose boss, the loose-boss is taken off from the arbor. Therefore, because the hard rubber material of the loose-boss is ground in the state when the arbor is fixed in the loose-boss, the surface of the hard rubber material is not finished finely.
Also, because a large weighting of 30 Kg is added to this top roller and bending stress is centralized to the ball-grooves, the arbor is easy to bend as, for instance, the center of the arbor is bent more than 0.5 mm when the bending stress is added to the arbor. Also, the boring of the oiling hole is difficult because the oiling hole in the center axis of the arbor is small and deep. In this top roller, the oiling amount is insufficient because the loose-boss and the arbor are not disjointed and the amount of oiling is not visible.